This is a single arm, Open-Label, Phase 1/2 Study of ZN-d5 for the Treatment of Relapsed or Refractory Light Chain (AL) Amyloidosis.

A Single Arm, Open-Label, Phase 1/2 Study of ZN-d5 for the Treatment of Relapsed or Refractory Light Chain (AL) Amyloidosis. The first part of the study is phase 1 dose-escalation and the second part will be phase 2.

Key Inclusion Criteria:

1. Diagnosis of AL amyloidosis based on histopathology, the presence of characteristic appearance on electron microscopy, or mass spectrometry typing of amyloid.
2. Prior AL amyloidosis treatment and has received at least one, but no more than three lines of prior therapy;
3. At least 3 months from hematopoietic stem cell transplantation or the shorter of 60 days or 5 half-lives for biologics, small molecules, or investigational drugs prior to starting treatment;
4. Measurable disease defined by serum differential free light chain;
5. Assessment of t(11,14) status by FISH;
6. Eastern Cooperative Oncology Group performance status ≤2 ;
7. History of organ involvement
8. Adequate bone marrow function prior to first administration of study drug;
9. Adequate organ function;

Key Exclusion Criteria:

1. Presence of non-AL amyloidosis, including wild-type or mutated ATTR amyloidosis;
2. Diagnosis of multiple myeloma according to the 2014 International Myeloma Working Group diagnostic criteria;
3. Mayo 2012 Stage IV disease;
4. Cardiac involvement exclusions apply to some subjects, including heart failure and cardiac arrhythmias.
5. Prior treatment with other BCL-2 inhibitors;